Novel CO2/N2 Foam Concept and Optimization Scheme for Improving CO2-foam EOR Process

2021 ◽  
Author(s):  
Rahul Gajbhiye

Abstract Nitrogen and Carbon dioxide are the most common gases utilized in enhanced oil recovery (EOR) techniques. Most of the gas injection process suffers from the gravity override and viscous fingering resulting in lower oil recovery. Foam is introduced in enhanced oil recovery (EOR) to mitigate these problems encountered during gas flooding. When it comes to the CO2-gas injection the CO2-becomes supercritical at a typical reservoir condition giving it difficulty to form CO2-foam at reservoir condition. The CO2-foam has a common problem to become weaker above its supercritical conditions of 1100 psi and 31°C. As a result, the advantages of using CO2 foam are diminished due to the weakness of CO2-foam at supercritical conditions and results in a lower recovery. However, CO2-foam can be generated by replacing a portion of CO2 with N2 gas. It lacks the understating of mixture properties and its effect on EOR. This study evaluates the performance of CO2/N2 foam at supercritical conditions for EOR. It aims to improve recovery under supercritical conditions by using N2/CO2 mixture foam and optimize the foam quality and CO2/N2 ratio. The results from the experiments showed that the CO2/N2 foam flooding recovered an additional oil of Original Initial Oil in Place (OIIP) indicating that foam flooding succeeded in producing more oil than pure CO2-foam injection processes. Also, the results of foam flooding at different foam quality and CO2/N2 ratio significantly affected the performance and recovery of the process. Hence it is necessary to optimize the CO2/N2 foam parameters flooding process which is affected by the parameters such as foam quality and CO2/N2 ratio. The study also shows an experimental approach for optimizing CO2/N2 foam parameters. The concept of adding N2 to CO2 is a novel way of generating CO2 foam at supercritical conditions. Although investigators are trying different ways to generate the strong and stable CO2- foam, adding N2 to CO2 can be considered to be the easiest way for foam generation as CO2 is always having some impurities in the form of other gases and N2 can be considered as one of such gas helps in generating the foam.

2018 ◽  
Vol 10 (2) ◽  
pp. 61
Author(s):  
Tjokorde Walmiki Samadhi ◽  
Utjok W.R. Siagian ◽  
Angga P Budiono

The technical feasibility of using flare gas in the miscible gas flooding enhanced oil recovery (MGF-EOR) is evaluated by comparing the minimum miscibility pressure (MMP) obtained using flare gas to the MMP obtained in the conventional CO2 flooding. The MMP is estimated by the multiple mixing cell calculation method with the Peng-Robinson equation of state using a binary nC5H12-nC16H34 mixture at a 43%:57% molar ratio as a model oil. At a temperature of 323.15 K, the MMP in CO2 injection is estimated at 9.78 MPa. The MMP obtained when a flare gas consisting of CH4 and C2H6 at a molar ratio of 91%:9% is used as the injection gas is predicted to be 3.66 times higher than the CO2 injection case. The complete gas-oil miscibility in CO2 injection occurs via the vaporizing gas drive mechanism, while flare gas injection shifts the miscibility development mechanism to the combined vaporizing / condensing gas drive. Impact of variations in the composition of the flare gas on MMP needs to be further explored to confirm the feasibility of flare gas injection in MGF-EOR processes. Keywords: flare gas, MMP, miscible gas flooding, EORAbstrakKonsep penggunaan flare gas untuk proses enhanced oil recovery dengan injeksi gas terlarut (miscible gas flooding enhanced oil recovery atau MGF-EOR) digagaskan untuk mengurangi emisi gas rumah kaca dari fasilitas produksi migas, dengan sekaligus meningkatkan produksi minyak. Kelayakan teknis injeksi flare gas dievaluasi dengan memperbandingkan tekanan pelarutan minimum (minimum miscibility pressure atau MMP) untuk injeksi flare gas dengan MMP pada proses MGF-EOR konvensional menggunakan injeksi CO2. MMP diperkirakan melalui komputasi dengan metode sel pencampur majemuk dengan persamaan keadaan Peng-Robinson, pada campuran biner nC5H12-nC16H34 dengan nisbah molar 43%:57% sebagai model minyak. Pada temperatur 323.15 K, estimasi MMP yang diperoleh dengan injeksi CO2 adalah 9.78 MPa. Nilai MMP yang diperkirakan pada injeksi flare gas yang berupa campuran CH4-C2H6 pada nisbah molar 91%:9% sangat tinggi, yakni sebesar 3.66 kali nilai yang diperoleh pada kasus injeksi CO2. Pelarutan sempurna gas-minyak dalam injeksi CO2 terbentuk melalui mekanisme dorongan gas menguap (vaporizing gas drive), sementara pelarutan pada injeksi flare gas terbentuk melaui mekanisme kombinasi dorongan gas menguap dan mengembun (vaporizing/condensing gas drive). Pengaruh variasi komposisi flare gas terhadap MMP perlu dikaji lebih lanjut untuk menjajaki kelayakan injeksi flare gas dalam proses MGF-EOR.Kata kunci: flare gas, MMP, miscible gas flooding, EOR


2015 ◽  
Vol 1104 ◽  
pp. 81-86 ◽  
Author(s):  
Malahat Ghanad Dezfully ◽  
Arezou Jafari ◽  
Reza Gharibshahi

In this study series of runs were done by a CFD technique in which the injected fluid is nanoparticles/supercritical CO2. Geometry of the porous medium was created with the commercial grid generation tool (Gambit software). Continuity, momentum and volume fraction equations were solved based on the finite volume method. The benefits of existing nanoparticles in the gas injection process have been investigated. The numerical results show that addition of nanosilica into the supercritical CO2improves the oil recovery. It was also found that by increasing the nanoparticles concentration from 1 Vol. % to 2 Vol. %, the oil recovery factor increases about 5%. In addition, obtained results confirmed that by injecting the nanofluid fingers are reduced. The displacing fluid containing nanoparticles is more efficient than the supercritical CO2in sweeping the in-situ oil.


2005 ◽  
Author(s):  
Frederic Maubeuge ◽  
Danielle Christine Morel ◽  
Jean-Pierre Charles Fossey ◽  
Said Hunedi ◽  
Jacques Albert Danquigny

2021 ◽  
Author(s):  
Thaer I. Ismail ◽  
Emad W. Al-Shalabi ◽  
Mahmoud Bedewi ◽  
Waleed AlAmeri

Abstract Gas injection is one of the most commonly used enhanced oil recovery (EOR) methods. However, there are multiple problems associated with gas injection including gravity override, viscous fingering, and channeling. These problems are due to an adverse mobility ratio and cause early breakthrough of the gas resulting, in poor recovery efficiency. A Water Alternating Gas (WAG) injection process is recommended to resolve these problems through better mobility control of gas, leading to better project economics. However, poor WAG design and lack of understanding of the different factors that control its performance might result in unfavorable oil recovery. Therefore, this study provides more insight into improving WAG oil recovery by optimizing different surface and subsurface WAG parameters using a coupled surface and subsurface simulator. Moreover, the work investigates the effects of hysteresis on WAG performance. This case study investigates a field named Volve, which is a decommissioned sandstone field in the North Sea. Experimental design of factors influencing WAG performance on this base case was studied. Sensitivity analysis was performed on different surface and subsurface WAG parameters including WAG ratio, time to start WAG, total gas slug size, cycle slug size, and tubing diameter. A full two-level factorial design was used for the sensitivity study. The significant parameters of interest were further optimized numerically to maximize oil recovery. The results showed that the total slug size is the most important parameter, followed by time to start WAG, and then cycle slug size. WAG ratio appeared in some of the interaction terms while tubing diameter effect was found to be negligible. The study also showed that phase hysteresis has little to no effect on oil recovery. Based on the optimization, it is recommended to perform waterflooding followed by tertiary WAG injection for maximizing oil recovery from the Volve field. Furthermore, miscible WAG injection resulted in an incremental oil recovery between 5 to 11% OOIP compared to conventional waterflooding. WAG optimization is case-dependent and hence, the findings of this study hold only for the studied case, but the workflow should be applicable to any reservoir. Unlike most previous work, this study investigates WAG optimization considering both surface and subsurface parameters using a coupled model.


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